The present invention relates generally to padlocks with a cylinder-guarding closure.
It is well known to provide padlocks with high security lock cylinders that are removable through an opening formed in the top surface of the padlock body. For example, U.S. Pat. Nos. 3,713,309 and 4,063,435 both describe arrangements for interchanging the lock cylinder through a top opening in the padlock body.
U.S. Pat. No. 3,636,738 describes a padlock with a cover plate having a very shallow surface hardening.
U.S. Pat. No. 3,710,603 describes a padlock with a sealing cover member that forms an upper closure for a bore for a cylinder.
U.S. Pat. 4,158,952 describes a padlock with a locking plug or cylinder which is removable through a top opening in the lock case. A top closure is provided in the form of a cap which is locked into the padlock case by a loose ball fitting in a groove in the cap and the case.
U.S. Pats. Nos. 3,713,309 and 4,241,594 describe a padlock with a key lock plug removably received in a plug cavity in the casing and an elongated slideway cavity overlying the plug cavity that extends through one end of the padlock casing outwardly adjacent the socket for the shorter leg of the shackle. The slideway cavity receives a reciprocative slidable cover member that covers the plug cavity.
U.S. Pat. Re. 30,243 describes a closure for a padlock body that comprises a circular member having a concave recess in its perimeter coacting with the shorter leg of the padlock shackle at the top of the padlock.
British Patent GB 2169343 describes a high security padlock including a removable lock mechanism within a lock body and a lockable shackle which can form a closed loop with the lock body. The lock mechanism is retained in the lock body by screw threaded means.
The present invention seeks to provide an improved padlock with a cylinder-guarding closure. The closure is a multifunctional lock top protector element overlying a bore of the cylinder so as to prevent access to the cylinder from the top surface of the padlock. Unlike the prior art, the shackle and the lock top protector element are configured such that when the shackle is locked by a locking mechanism of the padlock, the shackle locks said multifunctional lock top protector element in engagement with said top surface of said lock body and in overlying relationship with said bore.
It is noted that throughout the specification and the claims the term xe2x80x9cshacklexe2x80x9d is not restricted to a U-shaped shackle with two legs, but rather encompasses any kind of locking element or bolt which extends from a lock body, such as a single locking bolt or latch or any other kind of locking element.
There is thus provided in accordance with a preferred embodiment of the present invention a lock including a lock body defining a top surface and a bottom surface, the lock body having a bore formed therein extending from the top surface to a location spaced from the bottom surface, a key-operated lock cylinder located in the bore and having a keyway opening facing the bottom surface, a key entry aperture being formed in the bottom surface for permitting insertion of a key therethrough into engagement with the keyway opening of the cylinder and being sized so as not to permit the cylinder to pass therethrough, a shackle, a locking mechanism located in the lock body and being operated by the lock cylinder for locking the shackle, a multifunctional lock top protector element mounted onto the top surface of the lock body, the multifunctional lock top protector element being apertured to accommodate the shackle and to surround at least a portion thereof, the multifunctional lock top protector element overlying the bore so as to prevent access to the cylinder from the top surface, the shackle and the multifunctional lock top protector element being configured such that when the shackle is locked by the locking mechanism, the shackle locks the multifunctional lock top protector element in engagement with the top surface of the lock body and in overlying relationship with the bore.
In accordance with a preferred embodiment of the present invention the shackle is formed with at least one undercut which engages a corresponding portion of the multifunctional lock top protector element thereby locking the multifunctional lock top protector element in engagement with the top surface of the lock body and in overlying relationship with the bore.
Further in accordance with a preferred embodiment of the present invention the shackle includes a yoke having a pair of locking legs which are lockingly engaged by the locking mechanism.
Still further in accordance with a preferred embodiment of the present invention the lock also includes a key aperture cover assembly mounted on the bottom surface of the lock body.
Additionally in accordance with a preferred embodiment of the present invention the cylinder is formed with an apertured housing, pins and a plug which are configured such that the pins may be removed from the apertured housing via the apertures without removing the plug from the housing, when the plug is in a predetermined rotational orientation relative to the apertured housing.
In accordance with a preferred embodiment of the present invention the lock also includes a rotation restricting element that restricts rotation of the key-operated lock cylinder within a predetermined angular range, the rotation restricting element being selectively arrangeable with respect to the key-operated lock cylinder in two orientations, wherein in a first orientation the rotation restricting element permits rotation of the key-operated lock cylinder in a clockwise direction to open the lock and wherein in a second orientation the rotation restricting element permits rotation of the key-operated lock cylinder in a counterclockwise direction to open the lock.
Further in accordance with a preferred embodiment of the present invention the shackle is completely removable from the lock body.